A chromatography technique has been known to be used to separate desired molecules from a sample. This method repeats adsorption and desorption of molecules to and from what is called separation carriers to separate the molecules from one another based on a difference in mobility during a stochastic process (see, for example, Patent Literature 1). More specifically, for example, a sample containing various molecules is allowed to flow through a cylinder with porous particles (separation carriers) filled therein (a unit with such separation carriers filled therein is referred to as a “column”). Then, molecules smaller than pores in the separation carriers can enter the pores, but molecules larger than the pores cannot enter the pores and pass by the separation carriers. That is, the molecules smaller than the pores flow into and out of the pores and thus migrate at a reduced speed. The molecules larger than the pores cannot enter the pores and thus migrate fast. The molecules are separated from one another based on the difference in migration speed.